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| author |   Stefan-gabriel Mirea <stefan-gabriel.mirea@nxp.com> | 2019-08-09 11:29:16 +0000 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-04 12:43:54 +0200 |
| commit | 09864c1cdf5c537bd01bff45181406e422ea988c (patch) | |
| tree | a646e147848688a6edd6181029d200cf4b85ab2e /include/uapi/linux/serial_core.h | |
| parent | tty/serial: atmel: remove redundant assignment to ret (diff) | |
| download | linux-dev-09864c1cdf5c537bd01bff45181406e422ea988c.tar.xz linux-dev-09864c1cdf5c537bd01bff45181406e422ea988c.zip | |
tty: serial: Add linflexuart driver for S32V234
Introduce support for LINFlex driver, based on:
- the version of Freescale LPUART driver after commit b3e3bf2ef2c7 ("Merge
4.0-rc7 into tty-next");
- commit abf1e0a98083 ("tty: serial: fsl_lpuart: lock port on console
write").
In this basic version, the driver can be tested using initramfs and relies
on the clocks and pin muxing set up by U-Boot.
Remarks concerning the earlycon support:
- LinFlexD does not allow character transmissions in the INIT mode (see
section 47.4.2.1 in the reference manual[1]). Therefore, a mutual
exclusion between the first linflex_setup_watermark/linflex_set_termios
executions and linflex_earlycon_putchar was employed and the characters
normally sent to earlycon during initialization are kept in a buffer and
sent afterwards.
- Empirically, character transmission is also forbidden within the last 1-2
ms before entering the INIT mode, so we use an explicit timeout
(PREINIT_DELAY) between linflex_earlycon_putchar and the first call to
linflex_setup_watermark.
- U-Boot currently uses the UART FIFO mode, while this driver makes the
transition to the buffer mode. Therefore, the earlycon putchar function
matches the U-Boot behavior before initializations and the Linux behavior
after.
[1] https://www.nxp.com/webapp/Download?colCode=S32V234RM
Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
Signed-off-by: Adrian.Nitu <adrian.nitu@freescale.com>
Signed-off-by: Larisa Grigore <Larisa.Grigore@nxp.com>
Signed-off-by: Ana Nedelcu <B56683@freescale.com>
Signed-off-by: Mihaela Martinas <Mihaela.Martinas@freescale.com>
Signed-off-by: Matthew Nunez <matthew.nunez@nxp.com>
[stefan-gabriel.mirea@nxp.com: Reduced for upstreaming and implemented
earlycon support]
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Link: https://lore.kernel.org/r/20190809112853.15846-6-stefan-gabriel.mirea@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/uapi/linux/serial_core.h')
| -rw-r--r-- | include/uapi/linux/serial_core.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h index bd0d9d176a66..0f4f87a6fd54 100644 --- a/include/uapi/linux/serial_core.h +++ b/include/uapi/linux/serial_core.h @@ -290,4 +290,7 @@ /* Sunix UART */ #define PORT_SUNIX 121 +/* Freescale Linflex UART */ +#define PORT_LINFLEXUART 121 + #endif /* _UAPILINUX_SERIAL_CORE_H */ |